I love reading articles that discuss the same issue and come to essentially opposite conclusions. In this case, Canadian astronomers have recently performed an analysis of 2.5 million stars and found 234 of them producing pulsed signals that they claim may be of alien origin. The scientific community is skeptical.

When you read deep into both articles you find a more nuanced position. The difference is mostly in the headline writing, but also in the overall emphasis of the article. Skepticism can be marginalized or central.

SETI and Skepticism

I have found the search for extraterrestrial intelligence (SETI) to be an excellent topic of skeptical discussion. It is a great forum for discussing what is legitimate science, and how scientists decide whether something is likely to be true or not. There is nothing supernatural or paranormal about life evolving on exoplanets, intelligence emerging, and developing a technological civilization that might send signals out into space. We have done it.

What we have is an extreme dearth of data. We have, in fact, one data point – one example of life, let alone a technological civilization. Scientists are earnestly trying to figure out what is going on out there in the universe, but they have to extrapolate from little data.

The best argument for SETI is that there is no substitute for just looking. Let’s look at the universe and see what we find. Sure, interpreting what we find will be difficult, but without looking we have nothing.

Critics argue that without knowing exactly what we are looking for the whole endeavor is pointless. This is demonstrably false, in my opinion. Just look at the history of science. We often just look to see what we find and then carefully sift through the data to develop hypotheses, test those hypotheses, and then build theories. Otherwise, how could we ever discover anything entirely new?

How, then, is SETI different from ghost hunting? Putting aside the plausibility issue, I have no problem with people wanting to search for unlikely phenomena. My criticism of ghost hunting, at least in every single instance of which I am aware, is that their methods are pseudoscientific. They are not testing hypotheses, they are just anomaly hunting and then prematurely declaring whatever they find to be ghosts. They treat anomaly hunting as the end of their investigation.

SETI is also anomaly hunting, but they treat finding an anomaly as the beginning of their investigation. When astronomers find something odd they cannot immediately explain, it may be tempting to put “aliens” on the list of possible explanations, but they don’t just conclude that they are aliens (or at least they shouldn’t).

So, what process do SETI scientists go through? It is extremely thorough. First, they need independent confirmation. Other scientists using other telescopes or radio dishes need to find the same signal or anomaly. They also need to exclude all possible types of artifact or known natural phenomena.

All of this is simply to confirm that what they have is an actual anomaly. Ghost hunters don’t even do that. They find a cold spot and declare it “ghost cold” without even confirming they have an anomaly on their hands.

Once you have a genuine anomaly, you still don’t have aliens (that would be the argument from ignorance). What you have is unknown.

Scientists love the unknown. That is where the discoveries are. So far, every time astronomers have discovered a genuine anomaly they have eventually discovered a natural explanation. Most famously, when astronomers first discovered pulsars they were labeled LGMs for “little green men,” because of the precise timing of the pulses. Now we know they are rotating neutron stars that happen to be aiming their radio beams at Earth.

How then would we know that an anomaly is alien? That is a good question. Once we have a confirmed anomaly, then scientists will develop hypotheses and test them, looking for more examples of the anomaly. They will slowly build a case for one theory to explain the anomaly.

What would build the case for aliens? We don’t exactly know because we have no gold standard yet, but we suspect that an alien signal would contain coding in some fashion that is clearly technological and not natural. If, for example, it contained a sequence of prime numbers, that would be massive evidence of intelligence.

What is interesting is that, because of this process, we likely will not see a breaking news report where scientists will announce, out of the blue, that we discovered aliens. Instead we will see reports of some possible anomaly. The story will slowly develop as scientists confirm the signal, then rule out artifacts and natural causes, then search for other examples, and analyse the signal for more clues. This story may unfold over months or even years, slowly building greater and greater confidence that the signals or anomaly are actually alien in nature.

234 Anomalies

For the reasons stated above, there will be many instances of astronomers finding apparent anomalies, and we will just have to wait and watch the process unfold. Sure, aliens are on the list of possible explanations for any new astronomical anomaly, but only for thoroughness. History has shown that aliens being the explanation is statistically unlikely.

Right now there are two astronomical anomalies where aliens have not yet been ruled out, which does not mean I am holding my breath. The first, and actually more intriguing, anomaly is the star KIC 8462852, which experiences dips in light as great as 20%. Astronomers currently have no idea what is causing this unusual pattern of light dips. It probably isn’t alien megastructures, but it is fun to speculate about that. Right now we are in the genuine anomaly phase.

Now we have a new putative anomaly – Canadian astronomers EF Borra and E Trottier hypothesized that aliens may be trying to signal their presence with pulsed lasers. They examined data from 2.5 million stars, and found 234 of them producing light curves with a pattern similar to what they predicted. They write:

“Signals having the same period were found in only 234 stars overwhelmingly in the F2 to K1 spectral range. The signals cannot be caused by instrumental or data analysis effects because they are present in only a very small fraction of stars within a narrow spectral range and because signal to noise ratio considerations predict that the signal should mostly be detected in the brightest objects, while this is not the case.”

The fact that these signals are coming only from stars in a narrow spectral range, similar to our own sun, is odd if these are coming from alien civilizations. We don’t yet know what kind of star life is most likely to be found, but from what we know so far it is hard to explain such a narrow range. This is not a deal breaker, just odd.

With this find we are getting close to the genuine anomaly stage, but we are not quite there yet. The findings need to be vetted by the astronomical community more thoroughly. Even though this finding was not random – the astronomers were looking for similar signals – they were able to sift through 2.5 million stars to find their 234 candidates. That is a lot of data mining. The fact that they found what they were looking for should not be surprising.

In both cases we are likely to eventually find a natural explanation for these anomalies. That is the great thing about looking for alien signals – it’s a win-win. If you find an anomaly and it turns out to be some new astronomical phenomenon, you have still made an important discovery, even if it’s not that there is intelligent life elsewhere in the universe.

Conclusion

For now I am simply aware that there are these putative astronomical anomalies out there. There are probably more that have just not risen to the point of public attention. It is highly unlikely that any of them will turn out to be evidence for aliens. They will probably turn out to be fascinating astronomical discoveries.

But it is interesting to think that if we ever to do find convincing evidence of alien intelligence, the discovery will start out just like this. We will find an anomaly, and we will correctly think that it will probably not turn out to be aliens. Over years the evidence will slowly build, however, that something truly strange is going on, as natural candidates fall one by one.

We may even need to build new instruments to analyze the signal in more detail. Then perhaps features will emerge that are highly suggestive of an intelligent origin. Eventually the evidence will become overwhelming. It will just be a slow process.